A dosimetric comparison of MammoSite and ClearPath high-dose-rate breast brachytherapy devices.
OBJECTIVE
A new form of partial breast irradiation (PBI), ClearPath (CP) breast brachytherapy, has been introduced. We present our results of a dosimetric comparison of MammoSite (MS) and CP PBI.


METHODS
The dimensions of the CP device were reconstructed onto the MS planning CT scans for 15 previously treated patients. The mean %V(100), %V(150), %V(200) (percent of the PTV that received 100%, 150%, and 200% of the prescription dose, respectively), ipsilateral breast %V(50) (percent of the ipsilateral normal breast that received 50% of the prescription dose), ipsilateral lung %V(30) (percent of the ipsilateral lung that received 30% of the prescription dose), the heart %V(5) (percent of the heart that received 5% of the prescription dose), and the maximum skin point dose per fraction were then determined for each patient using the two methods of balloon-based PBI.


RESULTS
The mean %V(100) was 96.5% vs. 96.5%, the mean %V(150) was 42.1% vs. 42.9% (p=ns), and the mean V(200) was 11.4% vs. 15.2% (p<.05) for the MS and CP methods, respectively. The mean ipsilateral breast %V(50) was 19.8% vs.18.0% (p<.05), the mean ipsilateral lung %V(30) was 3.7% vs. 2.8% (p<.05), the mean heart %V(5) was 57.0% vs. 54.3% (p<.05), and the maximum skin point dose per fraction was 312.2 and 273.6cGy (p<.05) for the MS and CP methods, respectively.


CONCLUSIONS
The MS and CP methods of PBI offer comparable target volume coverage; however, the CP device achieves increased normal tissue sparing.
Dickler
Adam
A
Department of Radiation Oncology, Rush University Medical Center, Chicago, IL, USA. atd22_99@yahoo.com
Seif
Neil
N
Kirk
Michael C
MC
Patel
Mita B
MB
Bernard
Damian
D
Coon
Alan
A
Dowlatshahi
Kambiz
K
Das
Rupak K
RK
Patel
Rakesh R
RR
D001918:Brachytherapy / Q000295:instrumentation*; D001943:Breast Neoplasms / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D007496:Iridium Radioisotopes / Q000008:administration & dosage*; D011874:Radiometry; D011879:Radiotherapy Dosage
D007496:Iridium Radioisotopes